This invention relates to magnetic transducers, and to magnetically sensitive semiconductor devices, and more specifically to magnetically sensitive semiconductor devices suitable for fabrication in conventional integrated circuits. Various methods have been devised for detection of magnetically deflected carriers in semiconductors, but they all have very low sensitivity, usually less than 1%/kilogauss. Hereinafter, 1%/kilogauss means one percent differential change in the output current of the transducer per kilogauss magnetic field strength applied in the direction causing maximum change in the output current of the transducer.
The closest prior art magnetic transducers have operation based on differential collection of injected minority carriers preferentially deflected by a magnetic field to one or the other of two split collectors. Such magnetic transducers have very low sensitivity. Hall elements have been used on semiconductor chips as transducers having integrated circuit sensing amplifiers on the same chip, wherein the voltage across the Hall element is differentially sensed. But such devices are relatively inefficient, have high offset and power consumption, require a considerable amount of chip area, and are difficult to manufacture. None of the prior art devices is readily adaptable to fabrication in integrated circuits. The present invention solves the shortcoming of the prior art by providing a magnetically sensitive semiconductor device suitable for use in conventional integrated circuit structures, and having sensitivity much greater than 5%/kilogauss. The output of the magnetically sensitive device of the present invention may be detected and further amplified to a desired level by an integrated amplifier on the same chip.